lnd.xprv/channeldb/db.go
Olaoluwa Osuntokun 87603e780f channeldb: re-design OpenChannel schema, update tests
The state of OpenChannel on disk has now been partitioned into several
buckets+keys within the db. At the top level, a set of prefixed keys
stored common data updated frequently (with every channel update).
These fields are stored at the top level in order to facilities prefix
scans, and to avoid read/write amplification due to
serialization/deserialization with each read/write.

Within the active channel bucket, a nested bucket keyed on the node’s
ID stores the remainder of the channel.

Additionally OpenChannel now uses elkrem rather than shachain, delivery
scripts instead of addresses, stores the total net fees, and splits the
csv delay into the remote vs local node’s.

Several TODO’s have been left lingering, to be visited in the near
future.
2016-03-23 22:39:52 -07:00

156 lines
3.0 KiB
Go

package channeldb
import (
"bytes"
"encoding/binary"
"fmt"
"os"
"path/filepath"
"sync"
"github.com/boltdb/bolt"
)
const (
dbName = "channel.db"
)
var (
// Big endian is the preferred byte order, due to cursor scans over integer
// keys iterating in order.
byteOrder = binary.BigEndian
)
var bufPool = &sync.Pool{
New: func() interface{} { return new(bytes.Buffer) },
}
// EncryptorDecryptor...
// TODO(roasbeef): ability to rotate EncryptorDecryptor's across DB
type EncryptorDecryptor interface {
Encrypt(in []byte) ([]byte, error)
Decrypt(in []byte) ([]byte, error)
OverheadSize() uint32
}
// DB...
type DB struct {
store *bolt.DB
cryptoSystem EncryptorDecryptor
}
// Open opens an existing channeldb created under the passed namespace with
// sensitive data encrypted by the passed EncryptorDecryptor implementation.
// TODO(roasbeef): versioning?
func Open(dbPath string) (*DB, error) {
if !fileExists(dbPath) {
return nil, ErrNoExists
}
path := filepath.Join(dbPath, dbName)
bdb, err := bolt.Open(path, 0600, nil)
if err != nil {
return nil, err
}
return &DB{store: bdb}, nil
}
// Create...
func Create(dbPath string) (*DB, error) {
bdb, err := createChannelDB(dbPath)
if err != nil {
return nil, err
}
return &DB{store: bdb}, nil
}
// RegisterCryptoSystem...
func (d *DB) RegisterCryptoSystem(ed EncryptorDecryptor) {
d.cryptoSystem = ed
}
// Wipe...
func (d *DB) Wipe() error {
return d.store.Update(func(tx *bolt.Tx) error {
// TODO(roasbee): delete all other top-level buckets.
return tx.DeleteBucket(openChannelBucket)
})
}
// Close...
func (d *DB) Close() error {
return d.store.Close()
}
// createChannelDB...
func createChannelDB(dbPath string) (*bolt.DB, error) {
if !fileExists(dbPath) {
if err := os.MkdirAll(dbPath, 0700); err != nil {
return nil, err
}
}
path := filepath.Join(dbPath, dbName)
bdb, err := bolt.Open(path, 0600, nil)
if err != nil {
return nil, err
}
err = bdb.Update(func(tx *bolt.Tx) error {
if _, err := tx.CreateBucket(openChannelBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(closedChannelBucket); err != nil {
return err
}
if _, err := tx.CreateBucket(channelLogBucket); err != nil {
return err
}
return nil
})
if err != nil {
return nil, fmt.Errorf("unable to create new channeldb")
}
return bdb, nil
}
// fileExists...
func fileExists(path string) bool {
if _, err := os.Stat(path); err != nil {
if os.IsNotExist(err) {
return false
}
}
return true
}
// FetchOpenChannel...
func (d *DB) FetchOpenChannel(nodeID [32]byte) (*OpenChannel, error) {
var channel *OpenChannel
err := d.store.View(func(tx *bolt.Tx) error {
// Get the bucket dedicated to storing the meta-data for open
// channels.
openChanBucket := tx.Bucket(openChannelBucket)
if openChannelBucket == nil {
return fmt.Errorf("open channel bucket does not exist")
}
oChannel, err := fetchOpenChannel(openChanBucket, nodeID, d.cryptoSystem)
if err != nil {
return err
}
channel = oChannel
return nil
})
return channel, err
}